McDonald's new ad campaign highlighting its "Favorites Under 400 Calories" isn't just an attempt to highlight its healthier items during the Olympics; it's probably a preview of what's to come from restaurants around the country.

The oracles who read economic tea leaves have a host of conventional forecasting tools, but housing starts and job growth figures can only tell you so much. To cut through the haze of data, sometimes it takes an unconventional indicator -- for example, the Hair Index.

McDonald's, the world's largest hamburger chain, said global comparable sales grew 6.5% in October on strong performance of some local and value-menu items, as well as new offerings and store renovations.